In the art, different wireless communication technologies are known, which allow to activate wireless connections between two or more devices having reciprocal maximum distances of some tens of metres. Examples of such known wireless communication technologies are Bluetooth, Wi-Fi, Wibree, Zigbee, etc.
The most widespread applications of these wireless communication technologies are, for instance, connecting different computers within an office, connecting a computer to its peripherals (e.g. mouse, keyboard, modem, printer), connecting a digital camera to a computer, connecting a mobile phone to a headset, and so on.
For communicating by means of a wireless communication technology, a device must be provided with a suitable wireless interface. The wireless interface may be either integrated within the device, or it may be implemented as a stand-alone module which may be releasably connected to the device (such as for instance a “Bluetooth dongle”, which may be releasably connected to a computer by means of its USB port).
The mechanism allowing two or more devices provided with respective wireless interfaces to connect each other depends of the specific wireless communication technology.
For instance, in case of Bluetooth, a Bluetooth interface is typically configured to perform a so-called “discovery”, i.e. an operation of detecting whether further Bluetooth interfaces willing to activate a wireless connection are located within its coverage area. For signalling its presence and willingness to activate a wireless connection, each of the further Bluetooth interfaces broadcasts information comprising its identifier, Bluetooth address and supported Bluetooth profile(s). In particular, each Bluetooth profile indicates the operations that the device including the further Bluetooth interface may perform by using the wireless connection supported by the further Bluetooth interface. For instance, the “Bluetooth Headset Profile”, which is typically supported by headsets and mobile phones, provides the capability of receiving and transmitting voice signals encoded according to PCM (“Pulse Code Modulation”).
When, by means of a discovery, a first Bluetooth interface detects a second Bluetooth interface willing to activate a wireless connection and supporting a compatible Bluetooth profile, it preferably performs an authentication of the second Bluetooth interface, upon which the wireless connection is activated.
Further, Bluetooth provides a so-called “pairing” mechanism. In particular, according to the pairing mechanism, when a first Bluetooth interface of a first device (e.g. a headset) detects a second Bluetooth interface of a second device (e.g. a mobile phone) willing to activate a wireless connection and supporting a compatible Bluetooth profile (e.g. the Bluetooth headset profile), the first Bluetooth interface sends a pairing request to the second Bluetooth interface, which accordingly instructs the second device to present its user with a request to insert a PIN code for authentication. If the first and second devices belong to different users, the PIN code is typically agreed by the users before the pairing procedure is started and is explicitly inserted at the first device before sending the pairing request. On the other hand, if both devices belong to a same user or the first device doesn't include any input means allowing the user to insert the PIN code, the PIN code may be predefined by the manufacturer of the first device, and then communicated to the user e.g. by reporting it on the operating manual of the first device.
If the authentication succeeds, the first Bluetooth interface records the second Bluetooth interface as a “trusted” interface and vice versa. Both the first and the second device use the PIN code for generating a secure key that the they store and use for automatically authenticating each other, thus avoiding asking any further manual intervention by the user.
A Bluetooth interface may have more than one “trusted” interface, each one being recorded at the Bluetooth interface by means of a respective pairing procedure. The release of a connection between “trusted” interfaces typically has to be manually performed by the user.
US 2007/0249286 discloses a method and apparatus for managing the establishment of a wireless connection between an instrument host and a non-fixed device. The method comprises acquiring the non-fixed medical device address over a fixed wire by replacing the traditional wireless searching mechanism. The method also comprises providing an authentication mechanism between the instrument host and the non-fixed device, for example, across a wireless communications network.
US 2008/0016537 discloses a security token access device, a user device such as a computing device or communications device, and a method for managing multiple connections between multiple user devices and the access device. The access device maintains connection information, including security information, for each user device securely paired with the access device. Each time a new user device is paired with the access device, the access device transmits a notification to the user devices already paired to the user device. A user may provide instructions to the access device to terminate a pairing with one of the user devices by overwriting at least a portion of the connection information associated with the designated user device. A user device may further request a listing of all user devices currently paired with the access device.
WO 2006/120582 discloses a wireless communication between a mobile telephone handset and a headset worn by a person that uses the handset, through a first, wireless link such as Bluetooth. A second communication link is established by passing electrical currents between the handset and the headset through the body of the person. Communication through the second link is used to control operation of the first link.